1. Field of the invention
The invention relates to devices for immobilizing motorized chairs during times when the chair and its occupant are being transported in a motor vehicle. The invention is especially concerned with devices capable of clamping motorized chairs of the type having two relatively small rear wheels and a single forward steering wheel, as contrasted with chairs having a rear pair of large wheels on opposite sides of the chair and a forward pair of small stabilizing wheels.
2. Prior Art
A search turned up the following U.S. Pat. Nos.:
______________________________________ Seeley 1,753,838 Nelson 4,093,303 Barclay 1,835,840 Seay, et al. 4,246,984 Barclay 2,101,210 Howard 4,588,340 Tullock 4,083,594 ______________________________________
Seeley was cited for its disclosure of an overcenter linkage interconnecting a floor, or base, plate with the axle of a vehicle contained within a freight car in order to compress the vehicle's springs and enhance the immobilizing effect. While applicant's device includes an overcenter linkage, the respective linkages operate in different environments and the construction and operation of the Seeley's holddown is quite unlike that of applicant's claimed device.
Barclay '840 discloses means for locking a movable chair, having two relatively small rear-wheels, for transporting the chair in an automobile. This device involves a pair of guide rails for centering the chair, a feature which is essential for actuation of a hook-latch which engages a keeper installed on the chair. The structure and operation is at substantial variance from applicant's claimed clamp lock concept even though the objects of the two inventions are similar.
Barclay '210 offers a latching arrangement in which a U-shaped latch is snapped downwardly by a spring. This element and associated structure bear little resemblance to applicant's claimed device except that both devices relate to locking moveable chairs having a relatively small pair of rear wheels.
Tullock discloses means for holding large-wheeled wheel chairs in a motor vehicle; and is directed toward devices which are adjustable to compensate for variations in the lateral distance between the larger wheels of conventional wheel chairs. It bears but little resemblance to applicant's claimed device.
Nelson illustrates apparatus for retaining wheelchairs in a bus type motor vehicle; but, as in Tullock, the wheels are of the large type and the operation is dependent upon the force exerted by retaining arms and jaws on the chair's frame in urging the tires of the wheelchair against a fixed part of the bus frame or body. Applicant's claimed device is devoid of arms which embrace the wheelchair and, instead, restrains the small wheels of a small-wheeled chair by a combined frictional and positive interference effect.
Seay, et al. shows a safety apparatus that holds an occupied wheelchair in place as it is being transported in a motorized vehicle, such as a van. FIG. 4 and the accompanying description in Seay, et al. specifically disclose an apparatus for restraining the movement of chair wheels which are approximately six inches in diameter, such as those typically mounted on a motorized wheelchair, i.e. the kind of motorized chair with which the present application is concerned. Seay, et al., however, utilizes a yoke which is vertically slidable on an adjacent shaft, and the opening in the yoke captures a portion of the wheel. The construction and operation of the Seay, et al. apparatus is decidedly different from applicant's claimed device.
Howard discloses a method and apparatus for securing conventional (large wheel) and small-wheel, carriage-type (motorized) wheelchairs. In Howard, the "wheel locking component includes locking elements which extend through the spokes of the wheels of the wheelchair . . . preventing rotation of the wheels about their horizontal axis and/or rotational movement of the wheels about vertical axis." Howard also utilizes a handle-locking component. Howard's disclosure, in short, is at marked variance from applicant's claimed device.